South Korea was hit with a cyberattack Wednesday. Specifically, the computer systems at two banks, three major broadcasters and other targets were hit. Some are pointing fingers at North Korea.

According to Symantec, the attack included the defacement of a Korean ISP and telecoms provider and also the crippling of servers belonging to several organizations. The defacement displays an elaborate animated Web page with sound effects, the firm reports, showing three skulls and including a message by the claimed attackers calling themselves the "Whois" team.

"The attack was first noticed when a number of Web sites began to experience problems," Symantec said in blog post. "Customers of banks could not access their online accounts and reports of other sites being down began to surface. While specific details are not known at this time, it has been reported that a number of sites affected had their hard drives wiped, leaving the affected computers in a crippled state."

Wiping Hard Drives

Symantec detects the suspected malware as Trojan Horse/Trojan.Jokra and WS.Reputation.1 and is currently performing a detailed analysis of it. However, the security company can already confirm that the malware performs several actions, including creating a file-mapping object to reference itself, killing two processes related to local antivirus/security product vendors.

The malware also enumerates all drives and begins to overwrite the master boot record and any data stored on it by writing the either the string "PRINCPES" or "HASTATI." This, Symantec said, will wipe all contents of the hard disk. The firm said the threat may also attempt to perform the same wiping actions on any drives attached or mapped to the compromised computer, and forces the computer to reboot by executing "shutdown -r -t 0," which renders the system unusable as the master boot record and contents of the drive are now missing.

"The results of the disk wiping actions are consistent with the major outages reported in that region," Symantec said. "Disk wiping is not a new activity, in a separate in August 2012, a number of Middle-Eastern organizations were hit by the W32.Disttrack (Shamoon) threat which caused a similar type of damage by wiping hard disks."

Attacks on Critical Infrastructure

Amrit Williams, CTO of Lancope, said that given previous rhetoric coming from nation-sponsored threats and incidents against government and enterprise targets in the United States, we have entered an era that will be marked by unprecedented attacks on critical infrastructure.

"No matter whether the attacks are originating in North Korea, China or other nation-states, ultimately the U.S. government needs to be accountable for ensuring that services such as critical infrastructure are available and the U.S. thrives," Williams told us. "Today, however, the U.S. is ill-prepared to deal with mainstream malware outbreaks and unsophisticated network intrusions, let alone a highly coordinated attack that would actually justify such a response."